SparkFun Forums

[Doormattg]

I'm realizing more and more that I don't have enough discrete components in my parts box, and those I do have are because I've built a project that required that specific device. I'm looking for suggestions on Diodes, Transistors and whatnot that I should be stocking as common parts. I'm far better at the MCU side of things than I am the discrete side of things, so I'm trying to learn as fast as possible.

For example, wandering around and collecting parts numbers, I've got these on my list so far:

1N4001
1N4148
2N2222
2N3906
2N3904

As far as I can see (and understand) some of those devices overlap in their specifications. Is there any reason to have both?

Any suggestions?

Thanks!

[Chupa]

1n4001s are used mainly a reverse polarity protection, for save guarding someone hooking a bat up the wrong way. At least thats all i use them for.

what about:
Decoupling caps
voltage regulators (7805, or whatever)
hefty supply of 10k resistors.

[oPossum]

The 1N400x series are often used for recitfication in 60 Hz power supplies. They are rated at 1A and rather slow. Get a 1N4002, 1N4003, or 1N4004 - higher voltage, same price (usually).

The 1N4148 / 1N914 are fast(er) low current diodes often used for a variety of signal conditioning task. Peak detect, clipping, etc... The current rating varies depending on what spec sheet you look at - 250 to 500 mA typical.

1N400x and 1N4148 are not interchangable - you need both.

A Schottky diode like a BAT85 is good to have too. They are fast and have a lower Vf than a 1N4148.

The 2N2222 is usually speced to handle more current then the 2N3904. I prefer the 2N4401 over either. They are all general purpose NPN, and usually interchangable.

The 2N4403 is similar to the 2N3906 - usually slightly better specs.

I use 2N4401/03 for everything - buy them in 500 or 1000 lots.

Some other parts...

2N7000 - Small signal FET that can be driven by 5V logic

7805 and 78L05 - Voltage regulators

5.1V Zener Diode

100 nF caps - decoupling

Resonators - Get 4, 8, 10, 12, 16, and 20 MHz - theyr'e cheap

LEDs

Op amps...

LM339 - Quad Comparator
LM324 - Old, but versitile - single supply ready
TL074/TL084 - Better than a LM324 (for audio, signal conditioning)

[saipan59]

Other ideas:

LM358 op-amp. Similar functionality to LM324, but it's a dual in an 8-pin package, which to makes it more useful than a 324. I think it may have a bit better specs than a 324 also.

Instead of TL074/84, I'd suggest TL072. It's a dual 8-pin instead of a quad 14-pin. I find that there's not so many cases where I need more than a dual.

Instead of a 7805 regulator, consider a more more modern LDO version such as LM2940. Check if the extra cost is worth it to you.

555 timer. Available in bipolar and CMOS versions.

LM317 or equivalent adjustable regulator.

Previous reply mentioned 100 nF (.1 uF) decoupling caps. I use a lot of .01 uF also.

A few small electrolytic caps, such as 10 uF and 100 uF.

Crystals (i.e. 7.3 Mhz), and small caps to go with MCU crystals. I use 18 pF.

Resistors: 1K, 4.7K, 10K, 100K would be my first choice. And add to that something in the neighborhood of 330-470 ohms - needed for current-limiting when driving LEDs from 5V.

A couple of pots (potentiometers); perhaps 10K and 1K.

DIP switches are handy to go along with MCU stuff, for setting modes and such.

Pete

[bigglez]

I'm realizing more and more that I don't have enough discrete components in my parts box, and those I do have are because I've built a project that required that specific device. I'm looking for suggestions on Diodes, Transistors and whatnot that I should be stocking as common parts. I'm far better at the MCU side of things than I am the discrete side of things, so I'm trying to learn as fast as possible.
.....
Any suggestions?

Greetings Doormttg,

I see you have some good suggestions from others. You haven't told us what you plan to do with these parts?

Are you an experimenter that tears down projects after a session? Or, are you building for keeps, and will never tear things down?

Do you build on clip-blocks or other non-solder breadboards? On proto boards (Vero, Vector, etc.)? Do you etch PCBs or use BatchPCB etc. for custom made boards? Are you using SMT/SMD parts now or in the future?

Thinking back to the genesis of my 'stash' of parts, I've done all of the above at various times. I bought some cabinets with small drawers and always bought a few more pieces than I needed for an experiment or project. I found out never buy what you don't need, even if there's a bargain at the local surplus store.

I did buy 200 pcs of every resistor value from 10R to 10M in 1/4W 5%. I think Digi-key has a kit for resistors and capacitors. Handy if you do a lot of analogue design, less so for digital and uC work. I've had to refill a few bins over the years - I must like some values more than others when there's an open choice.

I make a point to re-use the same part numbers and sometimes the same sub-circuits, even the same PCB sub-circuit layouts, on new projects. Alas, I've been doing this long enough for some favourite parts to become obsoleted (at least there are modern and often improved versions to be had).

This has propelled my 'stash' to higher volumes, sometimes found at local surplus stores and Hamfests, but more often bought as new materials on-line.

As I made the transistion to SMT/SMD I've had to duplicate my favourite parts in SMT and through hole styles ($$ ouch!). Going forwards I expect to buy less through hole parts for obvious reasons. My cabinet with drawers has been replaced by a collection of plastic 'shoe boxes' (Target, Walmart, etc.). Most of the parts I buy are double packaged (ESD safe) and the actual parts are so small I need the bag labels to identify them!

Another place to look for larger quantities is eBay or local stores with surplus inventory closeouts. I have purchased open reels of common value resistors, such as 10k 1/4W 5%, which are used all over my designs.

Comments Welcome!